Circuit breaker panelboard



May 19, 1964 F. KUSSY ETAL CIRCUIT BREAKER PANELBOARD 4 Sheets-Sheet 1 Filed July 27, 1960 INVENTORS H/AR/S .f. SHIV-BACK FPA/VK KUSSY MLTEP May 19, 1964 F. KUSSY ETAL 3,134,050

CIRCUIT BREAKER PANELBOARD Filed July 27, 1960 4 Sheets-Sheet 2 INVENTOR. AMER/S Z S K m/3 4 FPA/VK K U 8 8 Y 14444 75? T GA'QT'OA/ y 9, 1964 F. KussY ETAL 3,134,050

CIRCUIT BREAKER PANELBOARD Filed July 27, 1960 4 Sheets-Sheet 3 a 2215 c 223 2/5 fZ/a 2; 41 4 as {y FIE. Y 18 FIG. 38 FIG]. 38 6 m 7 40 8 42 FIG 5 Q Q 63 INVENTOR. xmee/s z arm/34m FRANK KUSSY M44 7'5? 7. 4 70M May 19, 1964 ussY ETAL 3,134,050

, CIRCUIT BREAKER PANELBOARD Filed July 27, 1960 4 Sheets-Sheet 4 INVENTOR. AMP/PIS Z STAA/BACK FRANK K033) "/44 75K 7. G/IETO/V United States Patent 3,134,050 CIRCUIT BREAKER PANELBOARD Frank Kussy, Birmingham, Mich, Harris I. Stanback,

Lexington, Ky., and Walter T. Garton, Holland Park,

London, England, assignors to Square D Company,

Park Ridge, 11]., a corporation of Michigan Filed July 27, 1960, Ser. No. 45,538 3 Claims. (Cl. 317-119) This invention relates generally to circuit breaker panelboards. More particularly, it relates to means for preventing substitution or replacement of circuit breakers of higher electrical rating for those of lower rating in such panelboards.

To facilitate economic mass production and distribution of molded case type circuit breakers, such circuit breakers and the panelboards therefor are presently constructed so that circuit breakers of ditferent electrical ratings have the same physical configuration and are normally interchangeable on the panelboard. Unfortunately, in residential and commercial establishments unauthorized or inexperienced persons sometimes intentionally or inadvertently replace relatively low rated circuit breakers with those of higher rating. To combat this situation various regulatory bodies have enacted or contemplate enacting regulations which require, in effect, that panelboards and circuit breakers of specified electrical ratings for use therein be constructed so that such replacement cannot practically be carried out by unauthorized or inexperienced persons. Various approaches have been or are being proposed to comply with these regulations. 7 In one approach, for example, the circuit breakers are actually locked in the panelboard by apparatus which requires special tools or special skill to circumvent. In another approach the circuit breakers are physical modified to key or code them in accordance with their electrical rating and the mounting panel assembly within the panelboard or adapters therefor are complementally modified so that only similarly modified and similarly rated circuit breakers can be substituted for each other.

Accordingly, it is an object of this invention to provide improved panelboards and circuit breakers therefor which comply with the aforesaid regulations and employ the latter approach.

Another object is to provide improved mounting panel assemblies, circuit breakers and adapting means to carry out the aforesaid object, said adapting means being readily attachable to the mounting panel assemblies in the field but not easily detachable by unauthorized or inexperienced personnel.

Still another object is to provide improved mounting panel assemblies which are adapted to accommodate adapting means of the aforesaid character which prevent substitution of circuit breakers of higher electrical rating for those of lower rating, said circuit breakers being modified in accordance with the invention so as to be complemental to the adapting means.

A further object of the invention is to provide adapting means of the aforesaid character which can be employed with known forms of mounting panel assemblies and circuit breakers after relatively minor changes are made in the mounting panel assemblies and circuit breakers, such changes not substantially altering the basic design of such apparatus.

An even further object is to provide panelboards, circuit breakers and adapters made in accordance with the invention which are reliable in use, tamperproof, relatively economical to manufacture, and well adapted to mass production techniques.

3,134,050 Patented May 19, 1964 Other objects and advantages of the invention will hereinafter appear.

Generally speaking, the present invention, of which two embodiments are herein disclosed, contemplates an enclosure box, a mounting panel assembly removably mounted therewithin, circuit breakers for removable attachment to the mounting panel assembly, said circuit breakers being provided with non-conductive portions which have been modified in accordance with the electrical ratings of the circuit breakers, and adapter devices or clips which are attachable to the mounting panel assembly, each device or clip being complemental in configuration to the modified portion of a specific circuit breaker. When a given adapter device or clip is attached to the mounting panel assembly, only a circuit breaker having a portion which is keyed to fit thereto can be employed at that location, and thus, replacement by a circuit breaker having a higher electrical rating and a differently modified portion is prevented. Whereas the adapter devices or clips are attachable to the mounting panel assembly without tools, they are virtually impossible to detach as far as the average person is concerned, although they can be removed by qualified skilled personnel if necessary.

The drawings illustrate preferred embodiments of the invention which will hereinafter be described in detail, it being understood that the embodiments illustrated are susceptible to modification with respect to certain details thereof without departing from the scope of the appended claims.

In the drawings:

FIG. 1 is a front elevational view of an electrical panelboard constructed in accordance with invention and having mounted thereon a plurality of adapter clips and circuit breakers constructed in accordance with the invention.

FIG. 2 is a view, partly in section, taken along line 22 of FIG. 1.

FIG. 3 is an isometric view of the right-hand side of the panel of the mounting panel assembly shown in FIGS. 1 and 2 and shows one type of adapter device or clip attached thereto.

FIG. 4 is an isometric view of the other side of the adapter device or clip shown in FIG. 3.

FIG. 5 is a side elevational view of a portion of a circuit breaker employed with the invention.

FIG. 6 is a side elevational view of a portion of another circuit breaker employed with the invention and of a portion of an adapter device or clip keyed thereto.

FIGS. 7 and 8 are views similar to FIG. 6 but showing other circuit breakers and adapter device keyed thereto.

FIGS. 9, 10, 11 and 12 are end elevational views of the members shown in FIGS. 5, 6, 7 and 8, respectively.

FIG. 13 is an isometric view of the right-hand side of another type of pan that may be employed in the mounting panel assembly shown in FIGS. 1 and 2 to carry out another embodiment of the invention and shows another type of adapter device or clip attached thereto.

FIG. 14 is an elevational view of the bottom of the adapter device or clip shown in FIGS. 13, 16 and 20.

FIGS. 15 through 18 are views, partly in section, and partly in end elevation, of portions of circuit breakers modified in accordance with the second embodiment of the invention, the respective adapter devices or clips therefor, and the pan, shown in FIG. 13, of the mounting panel assembly shown in FIG. 1.

FIGS. 19 through 22 are elevational views of the backs of the members shown in FIGS. 15 through 18, respectively.

FIGS. 1 through 12 disclose the first embodiment of the invention.

With reference to FIGS. 1 and 2, there is shown an electrical panelboard 10. The panelboard comprises a metal enclosure box 11 which has side walls 12 and a back wall 13. A trim member or cover 14 is secured to the enclosure box 11 by screws 15 which screw into threaded clamps (not shown) within the enclosure box. The trim member 14 overlies a hopper member 1411 which has frontal openings 16 to provide access to the interior of the enclosure box 11. The opening 16a which is provided in the trim member 14 is provided with a hinged door 17 which is supported by the trim member 14.

A mounting panel assembly 18 is secured, by any suitable means, to the back wall 13 of the enclosure box 11 and mechanically supports two parallel rows 19 and 20 of circuit breakers of the molded case type. The row 19 comprises the circuit breakers 21, 22, 23 and 24 which are identical to each other in general overall configuration, except for certain individual modifications made in accordance with the invention, hereinafter described in detail, and which are rated to trip, for example, at 70, 50, 30 and 20 amperes, respectively. The row 20 comprises the circuit breakers 21a, 22a, 23a, and 24a which are identical in all respects to the circuit breakers 21, 22, 23 and 24, respectively. For purposes of illustration, the circuit breakers in row 19 are shown attached to the mounting panel assembly but no adapter clips are employed therewith, whereas an adapter device or clip is employed with each circuit breaker in row 20 to effect non-interchange ability.

The mounting panel assembly 18 comprises a mounting pan or flanged member 25, the side edges of which are bent upwardly to form a pair of spaced-apart parallel upstanding flanges 26 and 27. The flanges 26 and 27 are provided with rolled-over bead portions 28 and 29, respectively, that function as elements of a mounting system for the circuit breakers in the rows 19 and 20, respectively.

As FIG. 3 best shows, the flange 27 of pan of panel assembly 18 is modified in accordance with the invention by the provision therein of a plurality of slots and a plurality of the punched-out projections 31 which, as will hereinafter appear, provide latching surfaces for cooperation with the adapter clips to secure the latter to the pan. Each adapter clip engages two of the slots 30 and one of the projections 31. However, adjacent adapter clips share one of the slots 30. It is to be understood that the flange 26 of pan 25 of the panel assembly 18 is also provided with slots such as 30 and punched-out projections such as 31 for the same purpose.

The first embodiment of the invention employs three adapter clips 40, 41 and 42 which are substantially identical in overall configuration and manner of attachment to the pan 25 of the panel assembly but differ in that the adapter clips 41 and 42 are provided with ears of different size whereas adapter clip has no such ears. The adapter clip 42, best seen in FIGS. 2, 3, 4, 8, and 12, will be described in detail, it being understood that the adapter clips 40 and 41 are similarly constructed except for the ears. The adapter clip 42, which is preferably fabricated from a single piece of high strength, heavy gauge spring steel, comprises a back wall 42a and two parallel side walls 42b and 420 which are integral with the back wall. The outer or upper portions of the side walls 42b and 420 are fashioned in the shape of hooks having the bights 42d and 42e, respectively, which are adapted to engage the rolled-over bead portion 29 of the flange 27 of the pan 25 of the panel assembly 18. The inner or lower portions of the side walls 42b and 420 are provided with the small hooks 42f and 42g, respectively, which extend therefrom and which are adapted to extend through and engage the edges of any two adjacent slots 30 in the flange 27. A relatively narrow, resilient tang 42h extendsfrom the outer or top edge of the back wall 42a of the adapter clip 42, is bent downwardly along the inside surface thereof, and is offset downwardly from the back wall by a transverse portion which terminates in a depending portion.

4 The strip 42h of the adapter 42 is resilient and is provided with an aperture 421' in the depending portion which is adapted to engage one of the projections 31 on the flange 27 of the pan 25 when the adapter clip is attached to the pan to lock the clip to the pan, as will appear. The side walls 42b and 420 of the clip 42 are provided with inwardly bent registry means or ears 42 and 42k, respectively. The side walls 41b and 41c of theadapter clip 41 are provided with somewhat shorter registry means or ears 41 and 41k, respectively, as FIGS. 7 and 11 show. The side walls 40b and 40c of the adapter clip 40 are provided with no ears, as FIGS. 6 and 10 show.

The adapter clip 42 is attached tothe pan 25 of the mounting panel assembly 18 at a desired location by engaging the larger hooks on the bead portion 29 of the flange 27 of the pan and by inserting the small hooks 42] and 42g through two of the slots 30 in the flange 27 at the desired location. The adapter clip 42 is then pressed inwardly and downwardly against the pan 25 so that the strip 4211 is biased toward the back wall 42b of the adapter clip and the aperture 421' in the strip engages the projection 31 on the flange 27 of the pan. The adapter clip 42 is thus locked to the mounting panel assembly and cannot readily be removed unless the strip 42h is sprung so as to disengage aperture 42i from the projection. This cannot ordinarily be accomplished from the top of the adapter clip 42 since a pair of bent-over tabs 52m provided on side walls 42b and 42c interfere with the insertion of any sort of prying tool. Removal of the adapter clip 42 and those similar thereto is effected by removal of the panel assembly 18 from the enclosure box 11 so that access to the bottom of the adapter clip can be had to spring the strip 42h of the clip 42.

The mounting panel assembly 18 further comprises a pair of longitudinally extending bus bars 32 and 33 which are rigidly mounted in spaced parallel relationship with respect to each other upon an insulating support 34 which is suitably secured to the pan 25. A plurality of terminal connectors 35, each of which is electrically and mechanically connected to one of the bus bars 32 and 33 in alternate arrangement lengthwise of the mounting panel assembly 18, extends transversely from an associated bus bar toward the other to define longitudinally spaced mounting areas for the circuit breakers and to provide for electrical connection of each circuit breaker to one of the bus bars.

The circuit breakers employed in the present invention may, for example, be the type of molded case circuit breaker more fully described in Patent No. 2,902,560 for Circuit Breaker issued September 1, 1959 to H. I. Stanback et al. and assigned to the assignee of the present invention, but modified as will hereinafter appear. The circuit breakers in the rows 19 and 20 are each provided with electrically conductive spring jaw clips such as the clips 36 and 37, shown in FIG. 2, of the circuit breakers 23 and 23a, respectively, which extend downwardly from the bottom of their respective circuit breakers for making electrical connection to the terminal connectors 35. Each pair of transversely aligned circuit breakers in the rows 19 and 20 is thus connected to one of the terminal connectors 35 and thus to one of the bus bars 32 or 33, as FIG. 2 makes clear. As FIGS. 2, 5, 6, 7 and 8 show, each circuit breaker in the rows 19 and 20 is provided near its outer lower end with a spring mounting clip 38 having spaced-apart spring jaws 38a and 38b which accept in clamping engagement the rolled-over bead portion 28 or 29, as the case may be, of the pan 25 of panel assembly 18. Each clip 38 is retained in a suitable recess 39 provided in its respective circuit breaker, as FIG. 2 shows. Clip 38 is not electrically energized and is preferably made from high strength spring steel. Engagement of the clip 38 with either head portion 28 or 29 of the pan 25 and engagement of the electrically conductive clips such as 36 and 37 of the circuit breakers with the terminal connectors 35 affords mechanical support of the circuit breakers on the mounting panel assembly 18. V

The circuit breakers 24a, 23a, 22a and 21a ar'e modified in accordance with the invention by having registry means or cut away portions provided in the walls of their casings as shown in FIGS. 5, 6, 7 and 8 respectively, and FIGS. 9, 10, 11 and 12, respectively, which figures show the portions of the casings of the circuit breakers adjacent their spring mounting clips 38.

FIGS. 5 and 9 show that the circuit breaker 24a has no modification. Accordingly, the circuit breaker 24a can be employed only at a space on the mounting panel assembly 18 where no adapter clip is present, since the width of the circuit breaker is greater than the horizontal transverse distance between the sides of the adapter clips 40, 41 and 42.

FIGS. 6 and 10 show that the circuit breaker 23a is modified by being provided with the indentations 23b on opposite sides thereof which are adapted to receive the side walls 40b and 40c of the adapter clip 40. The ears on the sides of the adapter clips 41 and 42 prevent employment of the latter clips with the circuit breaker 23a.

FIGS. 7 and 11 show that the circuit breaker 22a is modified by being provided with the indentations 22b on opposite sides thereof which are adapted to receive the side walls 41b and 410 of adapter clip 41 and further provided with the deeper indentations 220 on opposite sides thereof which are adapted to receive the ears 41 and 41k of the side walls 411'; and 410, respectively. The ears on the sides of the adapter clip 42 are larger than the ears on the side of the adapter clip 41 and prevent employment of the adapter clip 42 with the circuit breaker 22a.

FIGS. 8 and 12 show that the circuit breaker 21a is modified by being provided with the indentations 21b on opposite sides thereof which are adapted to receive the side walls 42b and 42c of the adapter clip 42 and further provided with deeper indentations 210 on opposite sides thereof which are adapted to receive the ears 42 and 42k of the side walls 42b and 420, respectively.

It is to be understood that the circuit breakers 21a, 22a, 23a, and 24a are identical in electrical rating and in modification to the circuit breakers 21, 22, 23 and 24, respectively. lit is preferred that the circuit breakers 21a, 22a and 23a be provided with an integrally formed projection 45 which is adapted to rest on the top edge of the back wall of the adapter clips which are employed with those respective circuit breakers, as FIG. 2 shows, to enable the circuit breakers to be removed more easily.

From all of the foregoing it is seen that, if no adapter clips are employed, each circuit breaker in row 19 in FIG. 1 is interchangeable with any other in that row despite the fact that they have different electrical ratings and different modifications. However, when the adapter clips are employed, no higher rated circuit breaker can be substituted for those of lower rating since the adapter clips interfere with its proper attachment to the panel assembly, although lower rated circuit breakers can be substituted for higher rated circuit breakers. Thus, if desired, the

circuit breakers 21a, 22a and 23a could be substituted for the circuit breaker 24a; 21a and 22a for 23a; and 21a for 22a.

The second embodiment of the invention comprises a mounting panel assembly similar to the mounting panel assembly 18 that has already been described but instead of the mounting pan 25 is provided with a mounting pan 50. The pan 50, shown in FIG. 13, has side edges which are folded upwardly to form a pair of spaced-apart parallel flanges, one of which is shown and designated by the numeral 51. The flange 51 is provided with a plurality of Y-shaped slots 52 along the outer or upper edge thereof and with a corresponding number of apertures 53 along the bend thereof which accommodate another form of adapter device or clip which will hereinafter be described.

The second embodiment of the invention employs four adapter devices or clips 54, 55, 56 and 57 which are preferably fabricated from high strength, heavy gauge spring steel.

- The adapter clip 54, shown in FIGS. 15 and 19 comprises a rounded outer head portion 54a from which a pair of resilient legs 54b and 540 extend inwardly. The legs 54b and 540 are provided with a pair of punched projections 54d and 54e, respectively, which engage a latching surface formed by the top or outer edge defining one of the apertures 53 in the flange 51 of the pan when the adapter clip 54 is attached to the flange. There is provided a rivet 70 which extends through a pair of holes 541 and 541' which are provided in the legs 54b and 54c, respectively, of the adapter clip 54. The rivet 70 serves to prevent the legs from being pried apart and also serves as a guide in the attaching of the clip to the flange by engaging the Y-shaped slot. The adapter clip 54 is not removable from the flange unless the legs 54b and 54c are pried apart, but the legs of the clip 54, and those hereinafter described, are not able to be pried apart unless the mounting panel assembly is removed from the enclosure box 11 so that the bottons or inner ends of the clips are accessible.

The adapter clip 55 is shown in FIGS. 13, 14, 16 and 20 and is similar to adapter clip 54 but, in addition, is provided with a pair of outwardly or upwardly extending registry means or arms 55 and 55g, the latter of which is shorter than the former, and is also provided with a rivet 70 which extends through (the holes 55h, 551', 55 and 55k which are provided in the arm 55 the legs 55b and 550, and the arm 553, respectively, of the adapter clip. The rivet 70 serves to prevent the arms and legs of the adapter clip 55 from being pried apart either to defeat the keying system, hereinafter explained, or to remove that adapter clip from the pan 50. When the adapter clip 55 is placed on the panel assembly, the rivet 70 is accommodated by the narrow portion which forms the inner end of bottom of the Y-shaped slot 52.

The adapter clip 56, shown in FIGS. 17 and 21, is substantially identical to the adapter clip 55 except that an extended portion 56l has been added to one side of the arm 56g thereof.

The adapter clip 57, shown in FIGS. 18 and 22, is substantially identical to the adapter clips 55 and 56 except that the registry means or arms 57 f and 57g are of equal height.

The second embodiment of the invention contemplates a type of circuit breaker similar to that hereinbefore described except that instead of modifying the casing or housing of the circuit breaker, the modification is made to the spring mounting clip. The FIGS. 15, 16, 17 and 18 and FIGS. 19, 20, 21 and 22 show portions of the circuit breakers 60, 61, 62 and 63, respectively, which are assumed to be rated at 70, 50, 30 and 20 arnperes, respectively. The circuit breakers 60, 61, 62 and 63 are provided with the spring mounting clips 64, 65, 66 and 67, respectively, which are understood to be associated with their respective circuit breakers in the same manner as was hereinbefore explained in connection with spring mounting clip 38 in FIG. 2. As FIGS. 15 through 18 show, each of the spring mounting clips 64, 65, 66 and 67 is provided with spaced-apart spring jaws similar to the jaws 38a and 38b hereinbefore described in connection with the circuit breakers in the first embodiment of the invention. However, since the pan 50 shown in FIG. 13 has no head on the flange 51 or its other flange (not shown), none of the circuit breakers 60, 61, 62 or 63 can be employed therewith unless the adapter clips of the second embodiment are employed since these adapter clips are each provided with a rounded outer bead portion.

FIGS. 15 and 19 show that the spring mounting clip 64 of the circuit breaker is provided with two outward- 1y projecting registry means or tabs 64a and 64b and thus can only be employed with the adapter clip 54 which has no arms.

FIGS. 16 and 20 show that the spring mounting clip 65 of the circuit breaker 61 is provided with one outwardly projecting registry means or tab 65b and thus is intended to be employed with the adapter clip 55 which has a short arm 55g.

The FIGS. 17 and 21 show that the spring mounting clip 66 of the circuit breaker 62 is provided with one outwardly projecting registry means or tab 66b which extends only half the width of the clip jaw and thus is intended to be employed with the adapter clip 56 which has the extended portion 56l at one side of the arm 56g thereof. a

The FIGS. 18 and 22 show that the spring mounting clip 67 of the circuit breaker 63 is not provided with any tabs and thus is intended to be employed with the adapter clip 57 which has the arms 57 and 57g which are of equal height.

From the foregoing it is seen that if none of the adapter clips of the second embodiment are employed, none of the circuit breakers can be attached to the mounting panel assembly which employs the pan 50 because the flange 51 thereof has no beaded edge for engagement with the jaws of the spring mounting clips of the circuit breakers. However, when the adapter clips are employed, no higher rated circuit breaker can be substituted for one of lower rating since the adapter clips and spring mounting clips would interfere with each other to prevent proper attachment of the circuit breaker to the mounting panel assembly. If desired, however, the lower rated circuit breakers could be substituted for the higher rated circuit breakers. For example, the circuit breaker 63 can be employed with the adapter clips 54, 55, 56 and 57; circuit breaker 62 with the adapter clips 54, 55 and 56; and circuit breaker 61 with the adapter clips 54 and 55.

We claim:

1. An electrical panelboard comprising a box including a back wall and a side wall, a circuit breaker mounting panel assembly including a mounting pan, said mounting pan being removably secured in said box on saidback wall and having a flange extending outwardly from said back wall generally parallel to said side wall, an adapter clip releasably secured on said flange, said adapter clip.

having a resilient portion exerting a force on said flange in a direction generally parallel to said back wall, cooperating means on said flange and on said resilient portion preventing removal of said adapter clip from said flange when said resilient portion is in engagement with said flange, and means on said adapter clip preventing disassociation of said resilient portion from said flange while said mounting pan is secured on said back wall, said resilient portion being accessible when said mounting pan is removed from said back wall to permit disassociation of said resilient portion from said flange and removal of said adapter clip, one of said flange and said adapter clip members having a head portion, and said adapter clip having registry means permitting a circuit breaker having a certain rating and including certain circuit breaker registry means to be mechanically mounted on said head portion at the location of said adapter clip and preventing another circuit breaker having a different rating and including different circuit breaker registry means from being mechanically mounted on said head portion at the location of said adapter clip.

2. An electrical panelboard comprising a box including a back wall and a side wall, a circuit breaker mounting panel assembly including a mounting pan, said mounting pan being removably secured in said box on said back wall and having a flange. extending outwardly from said back wall generally parallel to said side wall and terminating in a rolled-over head portion, said flange having a pair of slots spaced longitudinally therealong and a latching surface spaced midway between said slots, and an adapter clip releasably secured on said flange, said adapter clip including a back wall having a resilient tang depending from an outer edge thereof and a pair of side walls having outer hook portions respectively hooked over said bead portion, inner hook portions respectively hooked on said flange through said slots, and inwardly bent tab portions extending over said resilient tang, said resilient tang being biased into cooperative association with said latchng surface to retain said adapter clip on said flange and said inwardly bent tab portions preventing disassociation of said resilient tang from said latching surface while said mounting pan is secured on said back wall of said box, said resilient tang being accessible when said mounting pan is removed from said back wall of said box to permit disassociation of said resilient tang from said latching surface and removal of said adapter clip, and said adapter clip having registry means on said outer hook portions permitting a circuit breaker having a certain rating and including certain circuit breaker registry means to be mechanically mounted on said head portion at the location of said adapter clip and preventing another circuit breaker having a different rating and including different circuit breaker registry means from being mechanically mounted on said bead portion at the location of said adapter clip.

3. An electrical panelboard comprising a box including a back wall and a side wall, a circuit breaker mounting panel assembly including a mounting pan, said mounting pan being removably secured in said box on said back wall and having a flange extending outwardly from said back wall generally parallel to said side wall, said flange having a slot opening to an outer edge thereof and having an aperture disposed inwardly of said slot and forming a latching surface on said flange, and an adapter clip releasably secured on said flange, said adapter clip including an outer bead portion, a pair of resilient legs extending inwardly from said bead portion and respectively biased into engagement with opposite sides of said flange, said legs respectively having projecting portions in cooperative association with said latching surface to retain said adapter clip on said flange, and a rivet extending through said legs and disposed adjacent the inner .end of said slot, said rivet preventing disassociation of said projecting portions from said latching surface while said mounting pan is secured on said back wall, said legs being disengageable from said flange when said mounting pan is removed from said back wall to permit disassociation of said projecting portions from said latching surface and removal of said adapter clip, and said adapter clip having registry means on said legs permitting a circuit breaker having a certain rating and including certain circuit breaker registry means to be mechanically mounted on said bead portion and preventing another circuit breaker having a different rating and including different circuit breaker registry means from being mechanically mounted on. said bead portion.

References Cited in the file of this patent UNITED STATES PATENTS 2,883,587 Dorfman Apr. 21, 1959' 2,902,632 Stanback Sept. 1, 1959 2,910,629 Casey Oct. 27, 1959 2,910,630 Hammerly Oct. 27, 1959 2,974,256 Cole Mar. 7, 1961 3,037,153 Koenig May 29, 1962 3,054,025 Edmunds Sept. 11, 1962' 

1. AN ELECTRICAL PANELBOARD COMPRISING A BOX INCLUDING A BACK WALL AND A SIDE WALL, A CIRCUIT BREAKER MOUNTING PANEL ASSEMBLY INCLUDING A MOUNTING PAN, SAID MOUNTING PAN BEING REMOVABLY SECURED IN SAID BOX ON SAID BACK WALL AND HAVING A FLANGE EXTENDING OUTWARDLY FROM SAID BACK WALL GENERALLY PARALLEL TO SAID SIDE WALL, AN ADAPTER CLIP RELEASABLY SECURED ON SAID FLANGE, SAID ADAPTER CLIP HAVING A RESILIENT PORTION EXERTING A FORCE ON SAID FLANGE IN A DIRECTION GENERALLY PARALLEL TO SAID BACK WALL, COOPERATING MEANS ON SAID FLANGE AND ON SAID RESILIENT PORTION PREVENTING REMOVAL OF SAID ADAPTER CLIP FROM SAID FLANGE WHEN SAID RESILIENT PORTION IS IN ENGAGEMENT WITH SAID FLANGE, AND MEANS ON SAID ADAPTER CLIP PREVENTING DISASSOCIATION OF SAID RESILIENT PORTION FROM SAID FLANGE WHILE SAID MOUNTING PAN IS SECURED ON SAID BACK WALL, SAID RESILIENT PORTION BEING ACCESSIBLE WHEN SAID MOUNTING PAN IS REMOVED FROM SAID BACK WALL TO PERMIT DISASSOCIATION OF SAID RESILIENT PORTION FROM SAID FLANGE AND REMOVAL OF 